The advent of instant soup mixes and other convenience foods of the dry variety has greatly increased the need for pasta products which will rehydrate within a short time to provide a product ready for immediate consumption.
Pasta products are conventionally made by moistening a mixture of dry ingredients with an amount of water only sufficient for compaction and plasticizing for forming the dough into the desired shape. Typical moisture contents for the dough stage are in the 30-34% by weight range. The dough may then be formed into a homogeneous sheet by successive passages between opposed heavy steel rolls, and the sheet is then continuously cut into noodle or macaroni pieces. Alternatively, extruders are used to form spaghetti and macaroni products. In this case, crumbly dough of about 30-34% moisture is prepared in a vacuumized mixer, and the product is then fed to an extruder. The extruder is specially designed so as not to have a progressive cross-sectional area reduction. The purpose of this is to provide conditions during extrusion whereby the relative natural dispositions of the gluten and starch components of the flour, as well as their chemical and physical integrity, are largely maintained by avoiding arduous shearing and heating during extrusion. Mechanically generated heat is removed by cooling the extruder barrel to minimize protein coagulation and starch gelatinization. The pasta mass is shaped to spaghetti or macaroni forms by auguring it under pressure through die apertures.
Products formed using the above-described prior art process require elaborate drying methods to insure that physical instabilities do not develop in the pasta during drying. Rapid moisture removal, as by using high temperature or low humidity convective air flow, sets up stress within the pasta, and checking or cracking of the product during cooking results. Conventional pasta making procedures preserve rawness, cell-integrity and nondispersion of protein and starch; conventional cooking times range from 8 to 10 minutes in actively boiling water.
Recent prior art methods for making a quickcooking pasta have adopted a number of approaches to the problem. U.S. Pat. No. 2,704,723 to Poole describes a process wherein the macaroni product is precooked prior to drying. The product requires a cooking time of 8-15 minutes and the cooked product is reported to have a slimy surface. In another approach, U.S. Pat. No. 3,192,049 to Kimsley et al. makes a dough containing hard wheat flour and added protein in the form of soy flour or wheat gluten. The dough is extruded, gelatinized by water or steam cooking, and dried. These products have a number of disadvantages including a complicated drying procedure, an undesirable flavor attributed to the high level of protein and a cooking time of 4-12 minutes in water at 97.degree.-100.degree. C.
U.S. Pat. No. 3,846,563 to Cunningham describes still another approach, where quick-cooking macaroni products are made using a precooked flour. The process described, while providing good quality products having a short cooking time, has the disadvantage of requiring relatively large amounts of energy.
More recent prior art processes are described in U.S. Pat. Nos. 4,098,906 to Hisaki et al. and 4,208,439 to Hsu. Hisaki et al. makes quick-cooking noodles with an aqueous emulsion of edible oil, heating the coated noodles with steam, and drying. Hsu makes an instant noodle by forming a sheet of gelatinized flour dough, subjecting the sheet to microwave energy to create therein pores of controlled size, shaping the pieces and drying. Each of these prior art processes require large amounts of energy, and the Hisaki process has the additional disadvantage of providing a product with a substantial oil content, which makes it unsuitable for many purposes.